1. Field of the Invention
The present invention relates to a play-back device such as an audio device, which includes a plurality of play-back sources having a play-back function of recording media such as a CD, an MD, a DVD and so on and a receiving function of an AM/FM radio broadcasts, and output units such as a speaker and a headphone for outputting sound based on the play-back signals from the individual play-back sources and which is provided with a function such as a dual media function to output sound based on the play-back signals from the different play-back sources simultaneously from both the speaker and the headphone.
2. Description of the Related Art
In recent years, the audio device having such dual media function is applied to a vehicular audio system.
FIG. 6 is a system construction diagram showing the entire construction of the vehicular audio system having a general dual media function.
The vehicular audio system 100, as shown in FIG. 6, includes: a body device 101 arranged on the front side in a vehicular compartment and provided with a plurality of play-back sources including a CD play-back function and a receiving function of an AM/FM radio; a front operation unit 102 for operating the body device 101 on the front side; a rear operation unit 103 for operating the body device 101 remotely on the rear side in the compartment; and a speaker 104 and a headphone 105 for outputting sound based on sound signals coming from the play-back sources of the body device 101.
The speaker 104 is composed of two front speakers 104A arranged on the front side, and two rear speakers 104B arranged on the rear side. On the other hand, the headphone 105 is arranged on the rear side.
Moreover, the play-back sources include the CD play-back unit and the AM/FM radio tuner unit, the latter of which acts as an AM tuner and an FM tuner so that it can receive the AM broadcast and the FM broadcast by itself.
Here, the front operation unit 102 corresponds to the front panel, as arranged on the front side, of the body device 101, and the rear operation unit 103 corresponds to the remote operation unit arranged on the rear side.
Moreover, the front operation unit 102 and the rear operation unit 103 are provided a play-back mode key for selecting at least one from a plurality of play-back sources, and a preset key capable of receiving the receiving frequency of the radio broadcasting station registered in advance, by a single-touch operation. Here, the play-back modes are exemplified in the CD mode for selecting and operating the CD play-back unit as the play-back source, the AM mode for selecting and operating the AM/FM radio tuner unit to receive the AM broadcast, and the FM mode for selecting and operating the AM/FM radio tuner unit to receive the FM broadcast.
Moreover, the body device 101 has a dual media function and can be switched and set to a single mode or a dual mode as the system setting mode in response to a predetermined operation from the front operation unit 102.
In the single mode, the sound based on the sound signals from one of the play-back sources are outputted exclusively from the speaker 104.
In the dual mode, the sound based on the sound signals from one of the play-back sources are outputted from the speaker 104, whereas the sound based on the sound signals from another play-back source are outputted from the headphone 105.
In case the body device 101 is demanded for provisions of sound signals from different play-back sources such that a passenger on the front side requests the FM mode whereas a passenger on the rear side requests the CD mode, the dual mode can be set by operating the front operation unit 102 in a predetermined manner. Then, the sound based on the sound signals of the FM broadcast can be outputted on the front side from the speaker 104, and the sound based on the sound signals from the CD play-back unit can be outputted on the rear side from the headphone 105.
In short, the front passenger and the rear passenger can accept the sound signals from the different play-back sources through the speaker 104 and the headphone 105.
According to the vehicular audio system 100 having such dual media function, the dual mode can be set in response to the predetermined operation of the front operation unit 102. In this dual mode, the sound signals from the different play-back sources can be provided through the speaker 104 and the headphone 105. Therefore, the front and rear passengers can listen to the sound signals from the different play-back sources.
According to the vehicular audio system 100 provided with the aforementioned general dual media function, however, if the FM mode is set on the rear side while the sound based on the play-back signals of the AM broadcast from the speaker 104 are being outputted by setting the AM mode on the front side, for example, the AM mode being set on the front side is switched to the FM mode because the single tuner acts as the AM and FM tuners.
In short, the following fluctuation occurs according to this vehicular audio system 100. The play-back signals (e.g., the play-back signals of the AM broadcast) to be outputted to the output unit (e.g., the speaker 104 or the output unit on the front side) other than at least one of the output units (e.g., the headphone 105 or the output unit on the rear side) are switched by the selection and change (e.g., the selective mode change) to the play-back source (e.g., the FM mode) relating to the play-back signals (e.g., the play-back signals of the FM broadcast) to be outputted to the at least one of the output unit (e.g., the headphone 105 or the output unit on the rear side) by the predetermined operation (e.g., the key operation of the mode selecting key of the rear operation unit).